The present specification generally relates to dynamic control, from network side, of network selection by terminals connecting to the network.
In network deployments like Long Term Evolution (LTE) or LTE-Advanced networks, in order to enable efficient offloading of traffic from the main radio link to e.g. Wi-Fi networks (Wi-Fi offloading), operators prefer having some degree of control over the terminal's (e.g. user equipment (UE)) Wi-Fi usage. All current major smart phone platforms (iOS, Android and Windows Phone) work such that, when a detected Wi-Fi network is known by the device (that is, a user or a provisioning server has configured certain Wi-Fi network details so that the UE can connect to that Wi-Fi network), the UE automatically connects to that Wi-Fi.
In such scenario, which Wi-Fi network is used by the UE can be only influenced by the operator (the network) by affecting which Wi-Fi networks are known by the UE.
Besides proprietary solutions to handle the above mentioned requirements of the operator/network, which are deployed only in very small scale, the Third Generation Partnership Project (3GPP) Access Network Discovery and Selection Function (ANDSF) provides standardized functionality which may handle the scenario described above. Namely, ANDSF server and UE client functionality is defined. ANDSF relies on an Open Mobile Alliance (OMA) device management (DM) framework for ANDSF information exchange between the server (i.e. the ANDSF Server) and client (i.e. the UE).
According to 3GPP specifications, ANDSF provides inter-system mobility policy (ISMP), Discovery Information as well as inter-system routing policy (ISRP), which are described below.
ISMP can be used to prioritize Wi-Fi networks over each other and also over 3GPP networks. ISMP is used when the UE does not support simultaneous 3GPP and Wi-Fi radio usage. An example of prioritized ISMP would be Wi-Fi with service set identifier (SSID)=Operator_A having highest priority followed by any Wi-Fi available, with 3GPP radio accesses having the lowest priority. Following this policy, the UE would connect to the network access of available network accesses having the highest priority according to the policy. ISMP was introduced in 3GPP Release 8.
Discovery Information can be used to tell the UEs where certain Wi-Fi networks are available. Each Wi-Fi network may be associated with a location area identifier that can be based e.g. on 3GPP identifiers (location area code (LAC), tracking area code (TAC) and/or cell identities (ID), etc.) to allow the device to optimize Wi-Fi scanning. Also, it is possible to configure Wi-Fi access details, like used extensible authentication protocol (EAP) methods and their respective credentials or pre-shared key (PSK) for certain Wi-Fi network. In practice, Discovery Information can be used to make Wi-Fi networks “known” to the UEs. That is, a UE is able connect to the identified Wi-Fi networks after receiving respective Discovery Information.
ISRP can be used to prioritize radio accesses for specific applications. Applications are identified with Internet protocol (IP) 5-tuples, e.g. with IP addresses, IP protocol and IP protocol port numbers. With Rel-11, it is also possible to identify traffic with fully qualified domain network (FQDN) or with operating system (OS)-specific Application ID. With ISRP, it is assumed that the device (i.e. UE) can use both 3GPP and Wi-Fi radio accesses simultaneously. An example of prioritized ISRP would be for YouTube traffic (identified application) Wi-Fi with SSID=Operator_A having highest priority followed by any Wi-Fi available, with 3GPP radio accesses having the lowest priority. Following this policy, the UE would use for the identified application the network access of available network accesses having the highest priority according to the policy.
Just to be complete, ANDSF management object (MO) can be used to convey location information of the UE to the ANDSF server during ANDSF session.
It is to be noted that ANDSF server and client implementations may support any combination of the above described ANDSF functionality.
It is further to be noted that ANDSF is not very suitable for real-time operations due to its dependency on the OMA DM framework.
In particular, setting up an ANDSF session can take several seconds. Further the transfer between the server and client of the actual ANDSF information may cause a further delay. Thus, the basic use model for ANDSF is such that the ANDSF information (ISMP, Discovery Information, ISRP) is provisioned to the UE, and then UE uses the same set of information for a certain period of time. Such period may for example be one week. Consequently, the actual ANDSF information can be considered as being static, which does not support a dynamic control.
Hence, the problem arises if UE only supports ANDSF Discovery Information and no ANDSF policies (neither ISMP nor ISRP). In such case a 3GPP operator can influence UE's Wi-Fi network selection by affecting which Wi-Fi networks are known by the UE, i.e. by the Discovery Information. Due to the static character of ANDSF information, the operator has almost no tools to affect in suitable time (i.e. nearly real time) which Wi-Fi networks can be selected by UEs. Such tools (kind of dynamic ANDSF) are needed to react in reasonable time to e.g. changing load conditions.
Hence, there is a need to provide the dynamic control of network selection.